The present invention relates to a fuel control apparatus for an internal combustion engine, and more particularly, to a fuel control apparatus employing an electronically controlled fuel injection device and the location thereof.
FIG. 1 shows a conventional fuel control apparatus for an internal combustion engine. An intake tube 1 connected to an intake port for an internal combustion engine is provided with a chamber 2 in which a fuel-air mixture is produced. A fuel injection valve 3 is provided in the chamber 2 for supplying fuel thereinto and a throttle valve 4 is provided downstream of the fuel injection valve 3 for controlling the flow rate of the fuel-air mixture. The fuel injection valve 3 is electrically connected to a control apparatus 5. The control apparatus 5 is in turn connected electrically to an incoming air sensor 6 provided in the intake tube 1 upstream of the fuel injection valve 3, for example an air sensor 6 of the hot wire type, and a water temperature sensor 8 provided on the body of the engine 7 for detecting the temperature of the water in a water cooling jacket.
According to the conventional apparatus as hereinabove described, an optimum quantity of fuel is calculated in the control apparatus 5 from the quantity of the incoming air and the engine temperature which are obtained by the air sensor 6 and the water temperature sensor 8, respectively. In accordance with the results of the calculation, the control apparatus 5 transmits a drive signal to the fuel injection valve 3, and controls the quantity of the fuel injected therethrough.
In the conventional arrangement the control apparatus 5 is mounted in the passenger compartment since the limitation as to the allowable temperature for its electronic parts makes it difficult to install the apparatus in the engine compartment in which a high temperature prevails. There is a considerable distance between the control apparatus 5 in the passenger compartment, and the fuel injection valve 3 and the air sensor 6 which are installed in the engine compartment. A considerable amount of wire and labor are, therefore, required for making electrical connections between the control apparatus 5 and the valve 3 or the sensors 6 and 8. Moreover, the wiring therebetween is likely to pick up undesirable noise from the wiring for other instruments.